Could both the food competition hypothesis and the sexual competition hypothesis explain why giraffes have long necks? Why or why not?

Evolution tends to act at which of the following levels?

With evolution as the core theme of biology, we can explain traits shared by organisms as evidence of __________ and traits that differ among organisms as evidence of __________.

What is the molecule that is responsible for both the unity and the diversity of life?

What does it mean to say that a characteristic is heritable?a. The characteristic evolves.b. The characteristic can be passed on to offspring.c. The characteristic is advantageous to the organism.d. The characteristic does not vary in the population.

What is 'selected' during natural selection? Explain your answer.

You read a blog that states, 'A squid's eye has been perfectly designed to see in the dark depths of the ocean.' Draft a paragraph that responds to the blog's use of the phrase 'perfect design' by citing an example discussed in this chapter.

Some humans have genes that make them resistant to infection by HIV. Would human populations likely evolve differently in areas of the world where HIV infection rates are high? Explain your logic.

Explain the role of heritable variations in Darwin's theory of natural selection.